Query creation in Spring Data - dynamic where clause

Question

Is there a way in Spring data to dynamically form the where clause?

What I want to do is have a method (which is like the findBy / get method) which runs a WHERE and

Answer 1

Another solution: You can extend your JPA repo interface using custom fragment interfaces.

1. Define your custom methods on a new interface

   public interface PersonFragRepository {
       List<User> findPersonByWhatever(
           String firstName, String lastName, String age, String gender);
   }
   

2. Provide the implementation

   public class PersonFragRepositoryImpl implements PersonFragRepository {
       @PersistenceContext
       private EntityManager entityManager;
   
       @Override
       List<User> findPersonByWhatever(
           String firstName, String lastName, String age, String gender) {
          ...
       }
   }
   

3. Extends your JPA interface

   public interface PersonRepository
       extends JpaRepository<Person, Integer>, PersonFragRepository
   

Answer 2

A even more simple option is to test if the parameter is null right in the JPQL query:

Exemple from my project:

@Query("select m from MessageEntity m " +
            "join fetch m.demandeAnalyseEntities d " +
            "where (:patientId is null or d.noPtn= :patientId) " +
            " and " +
            " ( :labNbr is null or d.noLab= :labNbr) " +
            " and " +
            " ( :reqDate is null or d.dteReq= :reqDate) " +
            " and " +
            " ( :reqNum is null or d.noReq= :reqNum) "
    )
    List<MessageEntity> findMessagesWithDemandesOnly(@Param("patientId") Long pid,
                                                     @Param("labNbr") Integer labNo,
                                                     @Param("reqDate") String reqDate,
                                                     @Param("reqNum") Integer reqNum,
                                                     Pageable pageable);

Answer 3

Take a look at JPA Specification and Predicate, and Even better QueryDSL, there both supported by spring data repositories. This article provide an example: http://spring.io/blog/2011/04/26/advanced-spring-data-jpa-specifications-and-querydsl/